Rotary air compressor including a sinuous tubular member presenting a series of compression chambers and pistons movable through said chambers

ABSTRACT

A rotary air compressor comprising a housing having a cylindrical wall and a pair of opposed flat end walls; a central drive disc mounted on a shaft journalled in the end walls and having a plurality of openings therein adjacent to the periphery thereof; a sinuous tubular member in said housing, arranged in spaced circular relation to the cylindrical wall of the housing and formed with a central slot normal to said shaft and receiving said disc to divide the tubular member into a plurality of compression chambers; a piston pivotally mounted on the disc at one end of each of said openings therein and swingable back and forth through the opening from a compression chamber on one side of the disc to a compression chamber on the other side; an air inlet manifold communicating with the compression chambers; an air outlet having a one-way check valve at one end of each compression chamber and communicating with a compression manifold; a conduit for conveying air under pressure from the compression manifold; a lubricating system for the shaft, disc and pistons, and seals for the disc and pistons.

[ Jan. 21, 1975 United States Patent [1 1 Hansen 1 ROTARY AIR COMPRESSOR INCLUDING A Primary Examiner.lohn J. Vrablik Attorney, Agent, or Firm.lohn A. Robertson SINUOUS TUBULAR MEMBER [57] ABSTRACT A rotary air compressor comprising a housing having a PRESENTING A SERIES OF COMPRESSION CHAMBERS AND PISTONS MOVABLE THROUGH SAID CHAMBERS cylindrical wall and a pair of opposed flat end walls; a central drive disc mounted on a shaft journalled in the [76] Inventor: Paul J. Hansen, 334 Interstate Pky.,

Bradford, Pa. 16701 July 20, 1973 end walls and having a plurality of openings therein adjacent to the periphery thereof; a sinuous tubular [22] Filed:

member in said housing, arranged in spaced circular relation to the cylindrical wall of the housing and Appl. No.: 381,029

formed with a central slot normal to said shaft and receiving said disc to divide the tubular member into a plurality of compression chambers; a piston pivotally mounted on the disc at one end of each of said openings therein and swingable back and forth through the opening from a compression chamber on one side of 2 %2 2 2 W/I 82 4 0 2 2 8 0 1 F. 8

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the disc to a compression chamber on the other side; an air inlet manifold communicating with the com- References Cited UNITED STATES PATENTS pression chambers; an air outlet having a one-way check valve at one end of each compression chamber and communicating with a compression manifold; a conduit for conveying air under pressure from the 8/1898 Hilton et 11/1931 2/1948 Booth 12/1973 Williams FOREIGN PATENTS OR APPLICATIONS compression manifold, a lubricating system for the shaft, disc and pistons, and seals for the disc and pistons.

599,609 3/1948 Great Britain.....,................ 418/218 11 Claims, 19 Drawing Figures 01L RESERVOIR [-ATEHTEDJANZI I975 SHEET 2 OF 5 FIE-E PATENTEDJANZI I975 SHEET 30F 5 FILE-5 FIE-5 FIE-5 PATENTED JANZ I I975 SHEET 5 OF 5 ROTARY AIR COMPRESSOR INCLUDING A SINUOUS TUBULAR MEMBER PRESENTING A SERIES OF COMPRESSION CHAMBERS AND PISTONS MOVABLE THROUGH SAID CHAMBERS The present invention relates to an air compressor which is also adapted for use as an hydraulic pump or a gas driven engine and is concerned primarily with a compressor including a sinuous tubular member that is divided by a central disc to define a plurality of compression chambers, with the disc being formed with openings and a piston for each opening pivotally mounted on the disc and swingable through the open ing from a compression chamber on one side to a chamber on the other side.

BACKGROUND OF THE INVENTION At the present time, it is known to provide apparatus of the class including air compressors, hydraulic pumps and gas powered engines, with a sinuous tubular member which is divided by a central disc or partition to define chambers in the tubular member on opposite sides of this disc. These chambers function as compression chambers and vanes are mounted in the disc to slide back and forth between the chambers on one side and those on the other. These vanes function in the manner of a piston. However, known apparatus of this type have not proven satisfactory to the degree necessary to meet with appreciable public acceptance for various reasons which are too involved to warrant a detailed explanation in this application.

The present invention is founded on the broad concept of providing the central disc with a plurality of openings and pivotally mounting a piston for each opening on the disc which swings back and forth through the opening from a compression chamber on one side to one on the other side, whereby the pistons continuously move throughout the entire circular extent of the sinuous tubular member.

OBJECTS OF THE INVENTION With the foregoing conditions in mind, the present invention has in view the following objectives:

I. To provide an air compressor which includes as characteristic and essential elements a housing comprising a cylindrical wall and end walls, a shaft journalled in the end walls, and a disc driveably mounted on the shaft. A sinuous tubular member is fixedly mounted in the housing and is divided by the disc into a plurality of compression chambers. The disc is formed with a plurality of openings and pivotally mounted on the disc is a piston for each opening which is swung through the opening from a compression chamber on one side to one on the other side.

2. To provide, in an air compressor of the type noted, an air inlet for each of the compression chambers.

3. To provide, in an air compressor the character aforesaid, an air outlet having a one-way check valve for each compression chamber and which communicates with a compression manifold.

4. To provide, in an air compressor of the kind described, a tubular member of rectangular cross-section and pistons having heads corresponding in shape to that of the tubular member, together with means for lubricating the edges of the piston head where they engage the walls of the tubular member.

5. To provide, in an air compressor of the type aforesaid. seals between the edges of the piston head and the walls of the tubular member.

6. To provide, in an air compressor of the character described, a lubricating system which provides for lubrication of the shaft, the pivotal mountings of the pistons, and the disc relative to the housing and tubular member.

7. To provide, in an air compressor of the type noted. seals for the edges of the piston head which are biased into engagement with walls of the tubular member by air pressure derived from the compression chambers.

8. To provide, in an air compressor of the kind described, seals between the pistons and the sides of the openings in the disc through which they pass.

Various other more detailed objects and advantages of the invention, such as arise in connection with carrying out the above ideas in a practical embodiment, will in part become apparent, and in part be hereafter stated as the description of the invention proceeds.

SUMMARY OF THE INVENTION The foregoing objects are achieved by providing an air compressor comprising a housing including a cylindrical wall and flat end walls in which a shaft is journalled. Drivably mounted on this shaft is a central disc formed with a plurality of equi-angularly spaced openings. A sinuous tubular member of rectangular crosssection is fixedly mounted in the housing in spaced relation to the cylindrical wall thereof and is circular or continuous. This tubular member is divided by the central disc into a plurality of compression chambers, some on one side of the disc and some on the other. Each compression chamber has an air inlet at one end which communicates with the atmosphere and an air outlet at the other end and having a one-way check valve. The air outlet communicates with a compression manifold which receives air under pressure generated by the pistons in the compression chamber.

Each piston includes a head of a shape corresponding to the cross-section of the sinuous tubular member and mounted on this head are seals which engage the walls of the tubular member under air pressure derived from the compression chambers. Seals are provided between the side walls of an opening through which a piston passes and the piston. Seals are also provided between the outer periphery of the disc and the housing and between the disc and the innermost wall of the tubular member. A lubrication system is provided which lubricates the shaft, the pivotal mountings of the pistons, the edges of the piston head and the surfaces of the disc which engage the housing and tubular member.

For a full and more complete understanding of the invention, reference may be had to the following description and the accompanying drawings wherein:

FIG. 1 is a perspective of an air compressor embodying the precepts of this invention with parts broken away to permit illustration of elements of the interior of the housing;

FIG. 2 is a side elevation of the disc with the pistons mounted thereon;

FIG. 3 is a detail perspective on an enlarged scale of one piston per se;

FIG. 4 is a section through a piston depicting an air valve and pumping unit therein and passages for the lubricating oil, being taken on the plane of the line 44 of FIG. 3;

FIG. 5 is a sectional view similar to FIG. 4 illustrating the air passages in the piston;

FIG. 6 is an end view, somewhat diagrammatic, of a piston head, being taken on the plane of the line 66 of FIG. 4;

FIG. 7 is an elevation, somewhat diagrammatic, of the rear seal which is designed for cooperation with the outer and inner peripheral surfaces of the tubular member;

FIG. 8 is a view similar to FIG. 7 of the front seal which cooperates with the side walls of the tubular member;

FIG. 9 is an elevation of the end plate of a piston;

FIG. 10 is a section through the end walls of the housing and the sinuous tubular member, with the latter flattened out to permit illustration in a single plane;

FIG. 11 is a fragmentary, sectional view illustrating two compressors assembled as a unit;

FIG. 12 is a detail elevation on an enlarged scale of a portion of the disc illustrating the seals between the disc and side walls of the tubular member;

FIG. 13 is a detail section on an enlarged scale illustrating the lubricating elements between the periphery of the disc and housing and sides of the disc, being taken on the plane of the line 13-13 of FIG. 12;

FIG. 14 is a detail view showing a portion of the piston in elevation and the sides of an opening in the disc in section and depicting the seals between the piston and the disc;

FIG. 15 is a perspective depicting the front seal, the rear seal and the back plate which are assembled on a piston head, in exploded relation;

FIG. 16 is a detailed section on an enlarged scale, taken on the plane of the line 16-46 of FIG. 15;

FIG. 17 is another detailed section, taken on the plane of the line 17-17 of FIG. 15;

FIG. 18 is another detailed section, taken on the plane of the line 18-18 of FIG. 15, and

FIG. 19 is still another detailed section, taken on the plane of the line 19-l9 of FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENT GENERAL ASSEMBLY Referring now to the drawings wherein like reference characters denote corresponding elements throughout the several views, and first more particularly to FIG. I, a housing is referred to generally as 10 and which is made of two parts to permit assembly. Thus, each part includes a cylindrical wall I] having end flanges 12 and 13. The two parts are what might be called mirror duplicates and are secured in assembled relation by bolts 14 which pass through flanges 13. A flat end wall 15 is secured to one part 11 by screw bolts 16, the inner ends of which are anchored to flange 12. Another end wall 17 is anchored to flange 12 of the other part 11 in a similar manner. Each of the end walls 15 and 17 is formed with a central opening 18 which receives one end of a bearing 19. Journalled in the bearings 19 is a shaft 20 and drivably mounted on shaft 20 is a central disc 21.

Referring for the moment to FIG. 10, a sinuous tubular member is identified generally at 22. It is defined by elements which are formed integrally with housing 10. Thus, each cylindrical wall 11 is formed at its inner end with a ring-like plate 23 (FIG. 1) with a sleeve 24 extending outwardly therefrom towards an end plate and receiving a bearing 19. Formed integrally with plate 23 are channel members 25 which gradually decrease in depth from a maximum such as indicated at 26 in FIG. 10 to points of no depth as indicated at 27 in FIG. 10. These channel elements 26 on the plate 23 of one part cooperate with the channel elements on the other part to define the sinuous tubular member 22 which is of rectangular cross-section and which is divided by disc 21. This division results in the formation of four compression chambers 28, 29, 30 and 31, as illustrated in FIG. 10. Moreover. each plate 23 cooperates with one of the end walls to define a compression manifold 32. there being a compression manifold on each side of disc 21.

Disc 21 rotates relative to sinuous tubular member 22 and for the purposes of this specification the rotation will be considered as counter-clockwise, speaking with reference to the showing of FIGS. 1 and 10. Thus, at what might be called the leading end of each compression chamber 28, 29, 30 and 31 is an air inlet 33 which communicates with an opening (not illustrated) in one of the cylindrical walls 11. An air filter, also not illustrated, may be also associated with an air inlet at an appropriate point. At what might be called the trailing end of each compression chamber 28, 29, 30 and 31 is an air outlet 34 which communicates with one of the compression manifolds 32 and which includes a one-way check valve which permits air under pressure to pass through the outlet to a compression manifold 32, but prevents its return from a compression manifold to a compression chamber.

Referring to FIG. 2, disc 21 is shown as formed with three openings 35 between its outer periphery and circular flanges 36 which project from the opposite faces thereof, one being shown in FIG. 1. Each opening 35 has what might be called a leading edge 37 and a trailing edge 38. These terms are used with reference to the direction of rotation of disc 21. Spanning the side edges of each opening 35 adjacent to leading edge 37 is a pivot pin 39. Pivotally mounted on pivot pin 39 is a piston designated generally 40. This piston 40 is illustrated more clearly in FIG. 3 and for the purposes of this portion of the specification it is noted that it includes a head 41 of curved rectangular shape which corresponds with the cross-sectional shape of tubular member 22 which defines the compression chambers.

Referring now again to FIG. 1, it will be noted that each of the cylindrical walls 11 is formed with a passage 42 which communicates with the other and with the compression manifolds by way of openings 43. The end of one passage 42 at end plate 17 is closed by a plug 44, while a fitting 45 is mounted in the end wall 15 at the other end of passage 42 and constitutes a means for connecting a conduit thereto for conducting air under pressure to a place where its use is required.

At this point, it is desirable to briefly summarize the operation of the mechanism so far described. Shaft 20 is driven from a suitable source of power and rotates disc 21 in a counter-clockwise direction. This rotation draws the pistons 40 through the sinuous tubular member 22. When the head 41 of a piston first passes an inlet port 33, it draws air into the compression chamber therebehind. Thus, upon referring to FIG. 10, it will be noted that when a piston 40 first passes the inlet port 33 at the right hand side of a compression chamber 29, it draws air into the compression chamber 28. As this piston 40 moves towards the outlet 34 at the left hand side of chamber 29, piston 40 will swing through an opening 35 from the position which it occupied on one side of disc 21 to that on the other side. Moreover, this movement of the piston builds up pressure in the air in compression chamber 29, with the compressed air being forced out of outlet 34 at the left hand side of chamber 29. Thus, air under pressure is delivered to compression manifold 32 and its return to the compression chamber is inhibited by the one-way check valve in the outlet 34. Thus, air under pressure is continuously delivered to the compression manifolds 32 on both sides of the disc and passes through openings 43 to the passages 42 from which it is withdrawn at fitting 45.

THE LU BRICATING SYSTEM Upon referring to FIG. 1, it will be noted that an oil reservoir is indicated diagrammatically at 46. From this reservoir, a tube 47 extends to a fitting 48 mounted on the exterior of end wall I7. This fitting 48 communicates with a radial aperture 49 in bearing 19 to deliver oil to the interior surface of the bearing. Thus, the shaft is lubricated.

Shaft 20 is formed with an annular groove 50 on each side of disc 21, only one of these grooves being shown in FIG. 1. Shaft 20 is also formed with a groove represented at broken lines at 51 which communicates between the two grooves 50. Thus, the oil from fitting 48 passes along shaft 20 and bearing 19 on the side adjacent end wall 17 and collects in the groove 50 on that side and then passes through the groove 51 to groove 50 on the other side and lubricates the shaft 20 in bearing 19 on the side adjacent to end wall 15.

Referring now more particularly to FIG. 2, each face of disc 21 is formed with three grooves 52, the inner ends of which are tangential to and communicate with a groove 50. Due to the rotation of disc 21, oil is drawn from the groove 50 under centrifugal force and passes outwardly through groove 52. Each groove 52 is continued beyond a flange 36 to a point where it communicates with an axial passage 53 formed in a pivot pin 39. Each passage 53 opens onto the peripheral edge of disc 21.

Referring now more particularly to FIGS. 1 and 13, plates 23 meet in face-to-face engagement along plane 86 (FIG. 1) and at the inner edge of these meeting surfaces, plates 23 are cut away at an angle to provide a circular groove 87. Formed integrally with the peripheral edge surface of disc 21 are a plurality of oil scrapers 88.

A passage 9 extends through a cylindrical wall 11 (FIG. I) and an oil return tube 8 has one end connected to passage 9 and its other end to oil reservoir 46. During rotation of disc 21, oil is delivered to groove 87 and pressure on this oil is built up by scrapers 89. This pressure causes oil to pass through passage 9 and tube 8 to be returned to reservoir 46.

At this point, it will be noted that while a complete lubricating system is herein described, it is to be understood that it is possible to replace such a system by using materials which are impregnated with a lubricant.

Referring now more particularly to FIGS. 3, 4 and 5, piston 40 is of a triangular shape similar to a slice of pie and presents converging side surfaces 54. Extending between these surfaces is a cylindrical passage 55, the ends of which are counterbored as indicated at 56. Piston 40 is formed with another passage 57 which extends from the mid-point of passage 55 to the surface of the bore in piston 40 which receives pivot pin 39. Another passage 58 extends from passage 35 at a point substantially midway thereof to two legs 59 of a Y passage. From the outer ends of the latter passages 60 extend to passage 6I formed in the confronting faces of seals 62 and 63 to be later described in detail.

Piston 40 is formed with a pair of air passages 64, with the inner end of each air passage being connected to passage 55 immediately adjacent to a counterbore 56. A small piston 65 is received in each end of passage 55 and an expansion coil spring 66, which is interposed between these pistons, tends to urge them apart whereby they are imparted the capability to function as valves controlling the admission of air to the passages 64 and also as an oil pump to draw oil from passage 57 or force it through passage 58.

A plug 67 is screwed into each counterbore 56 and has a central bore 68 which permits air under pressure from a compression chamber on one side of a piston 40 to be effective on a small piston 65.

It is to be remembered that piston 40 swings back and forth through an opening 35 and during such swinging movement the side faces 54 of the piston are exposed to air pressure from the compression chambers. Thus, the pressure on one side is first greater than that on the other side and except for the moment that the pressures are equalized will gradually build up on the other. Thus, upon referring to FIG. 4, it will be noted that pressure on the side 54 at the bottom of this FIG. has caused air to pass through bore 68 at the bottom and move the piston 65 at the bottom into the position illustrated which opens the inner end of air passage 64 at the bottom. At the same time, piston 65 at the top is in abutting engagement with the plug 67 at the top and closes the air passage 64 at the top. That portion of the passage 55 between pistons 65 will contain oil and this oil is forced outwardly through passage 58 by this inward movement of piston 65 at the bottom.

When piston 40 reaches an intermediate position, the pressure on sides 54 are equalized and spring 66 will expand pistons 65 to create a partial vacuum which draws oil through passage 57 from the bore which receives pivot pin 39.

FIG. 5 illustrates the opposite of the condition which is depicted in FIG. 4, wherein air line 64 at the bottom is closed and air line 64 at the top is open.

THE SEALS FIGS. 3 and 4 depict a front seal 62 and a rear seal 63 which are included as a part of the head 41 of a piston 40. Piston 40 has a head face 69 which is curved as illustrated in FIGS. 4 and S and seals 62 and 63 when assembled on piston 40 have a corresponding curvature. However, for purposes of facilitating illustration and description, they are shown in a flattened out condition in FIGS. 6, 7 and 8 and in the curved configuration which actually obtains in FIG. 15. Referring first to front seal 62, which is made of any material now commonly used for seals, gaskets and the like, is of rectangular shape comprising two U-shaped members, each comprising a back 70 and legs 71. One leg 71 on one member 70 is formed with a corner notch 72 which receives a flange 73 on the leg 7 l of the other U-shaped member. These U-shaped members are susceptible of relative expansion and contraction under air pressure, as will be later described. It is notable that the back 70 illustrated at one side of FIG. 7 presents a surface 74 which engages and wipes along one side wall of tubular member 22, while the back 70 at the other side presents a surface 75 which engages the other side wall of tubular member 22.

The rear face of front seal 62 is formed with grooves 76 which confront similar grooves to be later described on the front face of the rear seal to define an endless lubrication passage 61 which communicates with passages 60 in piston 40.

Each back 70 of front seal 62 is formed with a groove 107 (FIG. which opens onto the inner edge thereof. Upon referring to FIGS. 5 and 6, it will be noted that ends of passages 64 communicate with a cross passage 82 and the ends of the latter open onto groove 107. Thus, air under pressure is delivered to grooves 107 to expand front seal 62. To accommodate this expanding action, the back 70 and legs 71 of both U-shaped members are formed with slots 77 which receive studs carried by a backing plate 80, as will be later described. Grooves 107 constitute air passage 61 of FIG. 4.

Back or rear seal 63 has a structural arrangement similar to that illustrated in FIG. 7, with the notable exception that it presents edge surfaces 108 and 109 which are urged by air pressure against the top and bottom wall surfaces of tubular member 22.

The backs and legs of the U-shaped members making up rear seal 63 bear the same reference characters as the backs and legs of the corresponding members of front seal 62, with the exception that primes have been added. Thus, as shown in FIGS. 7 and 15, rear seal 63 comprises two U-shaped members, each consisting of a back 70' and legs 71'. The inner edges of backs 70 are formed with grooves 110 onto which open cross passages 111 (FIG. 6) in piston 40. Thus, the U-shaped members of rear seal 63 are expanded by air under pressure conducted by passages 64 and 111 to grooves 110.

Seal 63 is also formed with slots 112 which receive the studs above mentioned which limit relative movement between the U-shaped members. Outstanding from the peripheral edges of the rear face of rear seal 63 are flanges 113 which define a recess that receives the center block of a backing plate 80 now to be described.

Backing plate 80 is of a curved rectangular shape generally corresponding to that of the seals. It carries a center block 114 which presents marginal portions 115 of the backing plate. Projecting forwardly from marginal portions 115 are a plurality of studs 116 which correspond in number and arrangement to slots 77 and 112 through which they pass.

Backing plate 80 is formed with four holes 117 through each of which passes a screw bolt 118, only one of which is illustrated. Bolts 118 are screwed into threaded sockets (not illustrated) in piston 40. It is center block 114 that is formed with passage 82 and transverse passages I11 illustrated diagrammatically in FIG. 6. Screw bolts 118 have heads 81.

FIG. 14 illustrates the seals between head 41 of a piston 40 and the sides of an opening 35 in disc 21. Thus, opening 35 presents a side surface 83 which is formed with a recess 84 in which a seal or packing 85 is received with a press fit. This seal 85 extends beyond surface 83 and engages the side surface of a piston 40. The same arrangement obtains at the other side of an opening 35 as illustrated at the bottom of this FIG.

Immediately below the corner surfaces defining groove 87, each plate 23 is cut away to provide an annular oil receiving recess 89, the innermost portion of which is defined by a conical surface 90. A seal 91 is received in recess 89 and the upper edges thereof are formed as sawteeth 92 as illustrated in FIG. 12. The inclined surfaces 92 ride over a cylindrical surface 93 which defines the outer wall of recess 89. Each seal 91 is formed with a groove 7 on the face which engages disc 21.

The radially inward side of each flange 36 is formed as a conical surface 94. Passages 95 extend from conical surface 94 to the cylindrical surface of each flange 36.

Each plate 23 is formed with an annular groove 96 which receives a flange 36. Groove 96 is continued beyond flange 36 to provide an annular recess 97 which receives a seal 98. The inner circular edges of seal 98 are also of a sawtooth configuration as illustrated in FIG. 12 to define inclined surfaces 99 which ride over the cylindrical surface of recess 97 which is serrated to provide a sawtooth configuration of seal 98.

It will be noted from FIG. 2 that each of the oil conducting grooves 52 extends to flange 36. FIG. 13 shows the upper portion of one of these grooves as terminating in recess 96. FIG. 2 also illustrates the groove 52 as being continued beyond the upper edge of flange 36. Thus, oil is conducted from flange 36 to the inner end of the bores 53 in pivot pins 39 to inner recess 96 as illustrated in FIG. 12. It is evident that the sawtooth surfaces 92 and 99 accommodate wear on the seals as they ride over the surfaces of grooves 89 and 96. Seals 98 do not rotate, but are dragged by surface friction of rotating disc into what might be considered a binding seal, thus necessitating lubricating grooves 7 (FIG. 13).

As mentioned above, the subject rotary air compressor is adapted for use as a gas powered engine. When so used, the seals 91 and 98 will have their sawtooth edges reversed so as to accommodate rotation of disc 21 in a clockwise direction which would be the condition which obtains if gas under pressure is introduced to the compression chambers.

THE MODIFICATION FIG. 11 illustrates an arrangement in which two of these air compressors may be combined as a single unit. Thus, the right hand portion of one compressor is designated generally at 100 and the left hand portion of another compressor at 101. Thus, for compressor 100 the end plate 15 is omitted and for compressor 101 the end plate 17 is omitted. These end plates are replaced by a cylindrical member 102 having end flanges 103 which are secured to the flanges 12 by bolts (not illustrated) similar to bolts 16. Passages 42 in the housing of FIG. I are connected by the space 104 provided by member 102. This structure provides a compression manifold comprising the confronting sides of the two compressors from which air under pressure passes through openings 43 to passages 42 and 104 which includes a plug at one end comparable to fitting 45 of FIG. 1. The shaft of each of the compressors 101 is designated 20 and the meeting end portions of these shafts are fluted as indicated at 105 and received in a splined sleeve 106 to establish the driving relation between the shafts. Thus, one compressor is driven from the other and only a single power source for driving the shafts 20 is required.

While preferred specific embodiments are herein disclosed, it is to be clearly understood that the invention is not to be limited to the exact constructions, mechanisms and devices illustrated and described because various modifications of these details may be provided in putting the invention into practice.

What is claimed is:

1. In a rotary air compressor,

a. a housing comprising a cylindrical wall and a pair of end walls secured to the opposite ends of said cylindrical wall;

b. a sinuous tubular member connected to said cylin drical wall and located therewithin in a circular arrangement;

c. a shaft journalled in said end walls and coaxial with said cylindrical wall;

d. a disc drivably mounted on said shaft midwawy said end walls and dividing said tubular member into a plurality of compression chambers, some on one side of the disc and some on the other side;

e. an air inlet at one end of each of said compression chambers and an air outlet at the other end of each of said compression chambers;

f. said disc being formed with a plurality of angularly spaced openings in the portion thereof which divides said tubular member into said compression chambers, each of said openings having a leading edge and a trailing edge;

g. a piston pivotally mounted at one end on said disc at the leading edge of each of said openings and swingable through that opening from a compression chamber on one side of the disc to one on the other side, said pistons having heads corresponding to the cross-section of said tubular member in which they are slidably received with a snug fit, and

h. a compression manifold defined by said housing on each side of said disc and communicating with the air outlets of the compression chambers on the adjacent side of said disc.

2. The rotary air compressor of claim 1 in which the sinuous tubular member is rectangular in cross-section and the heads of the pistons are of a similar rectangular cross-section.

3. The rotary air compressor of claim I, together with a lubricating system for lubricating the shaft relative to the housing, the disc relative to the housing and the surfaces of the compression chambers formed by the disc and the pivots of the pistons.

4. The rotary air compressor of claim 1, together with expansible air seals carried by the head of each piston and the edges of which engage surfaces of said tubular member.

5. The rotary air compressor of claim 4 in which said seals are expanded by air pressure derived from said compression chambers.

6. The rotary air compressor of claim I, together with seals between the sides of each opening and the piston which swings therethrough.

7. The rotary air compressor of claim 3 in which the lubricating system includes a passage which delivers oil to the pivotal mounting of each piston and in which the piston is formed with passages for conducting oil from the pivotal mounting to the head, expansible seals on the head on said piston, passages for conducting air from compression chambers to said seals and a pump and valve assembly for controlling the flow of air to said seals and for pumping oil from said pivotal mounting to the piston head.

8. The rotary air compressor of claim 1 in which the housing comprises two parts, each of which includes an end plate, a cylindrical wall section and an inner circular plate integral with said cylindrical wall section, said inner plates being in engagement and defining a slot which receives said disc.

9. The rotary air compressor of claim 8 in which said disc has opposed faces with an annular flange projecting from each face in spaced relation to the periphery of said disc and seals between each of said flanges and one of said inner plates.

10. The rotary air compressor of claim 8 in which each of said cylindrical wall sections is cut away where they meet to define an inwardly opening groove and an oil scraper on the periphery of said disc cooperating with said groove.

11. The rotary air compressor of claim 10 in which each face of an inner plate where it engages the disc is formed with an annular recess adjacent to its periphery and opening onto said disc and a seal in each of said re- CCSSGS. 

1. In a rotary air compressor, a. a housing comprising a cylindrical wall and a pair of end walls secured to the opposite ends of said cylindrical wall; b. a sinuous tubular member connected to said cylindrical wall and located therewithin in a circular arrangement; c. a shaft journalled in said end walls and coaxial with said cylindrical wall; d. a disc drivably mounted on said shaft midwawy said end walls and dividing said tubular member into a plurality of compression chambers, some on one side of the disc and some on the other side; e. an air inlet at one end of each of said compression chambers and an air outlet at the other end of each of said compression chambers; f. said disc being formed with a plurality of angularly spaced openings in the portion thereof which divides said tubular member into said compression chambers, each of said openings having a leading edge and a trailing edge; g. a piston pivotally mounted at one end on said disc at the leading edge of each of said openings and swingable through that opening from a compression chamber on one side of the disc to one on the other side, said pistons having heads corresponding to the cross-section of said tubular member in which they are slidably received with a snug fit, and h. a compression manifold defined by said housing on each side of said disc and communicating with the air outlets of the compression chambers on the adjacent side of said disc.
 2. The rotary air compressor of claim 1 in which the sinuous tubular member is rectangular in cross-section and the heads of the pistons are of a similar rectangular cross-section.
 3. The rotary air compressor of claim 1, together with a lubricating system for lubricating the shaft relative to the housing, the disc relative to the housing and the surfaces of the compression chambers formed by the disc and the pivots of the pistons.
 4. The rotary air compressor of claim 1, together with expansible air seals carried by the head of each piston and the edges of which engage surfaces of said tubular member.
 5. The rotary air compressor of claim 4 in which said seals are expanded by air pressure derived from said compression chambers.
 6. The rotary air compressor of claim 1, together with seals between the sides of each opening and the piston which swings therethrough.
 7. The rotary air compressor of claim 3 in which the lubricating system includes a passage which delivers oil to the pivotal mounting of each piston and in which the piston is formed with passages for conducting oil from the pivotal mounting to the head, expansible seals on the head on said piston, passages for conducting air from compression chambers to said seals and a pump and valve assembly for controlling the flow of air to said seals and for pumping oil from said pivotal mounting to the piston head.
 8. The rotary air compressor of claim 1 in which the housing comprises two parts, each of which includes an end plate, a cylindrical wall section and an inner circular plate integral With said cylindrical wall section, said inner plates being in engagement and defining a slot which receives said disc.
 9. The rotary air compressor of claim 8 in which said disc has opposed faces with an annular flange projecting from each face in spaced relation to the periphery of said disc and seals between each of said flanges and one of said inner plates.
 10. The rotary air compressor of claim 8 in which each of said cylindrical wall sections is cut away where they meet to define an inwardly opening groove and an oil scraper on the periphery of said disc cooperating with said groove.
 11. The rotary air compressor of claim 10 in which each face of an inner plate where it engages the disc is formed with an annular recess adjacent to its periphery and opening onto said disc and a seal in each of said recesses. 